drm/i915/display: implement wa_18038517565

Disable FBC compressor clock gating before enabling FBC and
clear it after disabling FBC.

v2: update the DG2 registers for this wa

v3: use local variable and single line reg definition (Jani)

Bspec: 74212, 72197, 69741, 65555
Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://lore.kernel.org/r/20250330172616.718188-1-vinod.govindapillai@intel.com